DE-AS 24 03 199 discloses a process wherein moulding sand is placed into a moulding box from a sand container by being shot through shooting apertures while compressed air is fed in such that the sand is pre-compacted. The re-compacting of the pre-compacted moulding sand in the moulding box is effected by a mutual approach of the pattern plate and the pressure plate.
Such process is disadvantageous since the patterns are subjected to a relatively great amount of wear due to the abrasive effect of the moulding sand particles accelerated by shooting them in. Moreover a substantial energy requirement is necessary for shooting-in the sand and this has an unfavourable effect on the cost structure of the mould production.
The attainment of a uniformly high degree of mould hardness, especially in the region of the mould near the pattern, is desirable not only in connection with a mould produced by shooting-in of the moulding sand, but also completely independently of the method of inserting sand into the moulding box. The requisite mold hardness is achieved with mechanical insertion of sand for example by shaking with subsequent mechanical pressing.
Since shaking is increasingly unpopular because of the noise and the vibrations associated therewith, there is a need to produce a uniformly good casting mould with technically satisfactory mould hardness by means of other, environmentally more pleasing and more productive methods.